A manually curated compendium of expression profiles for the microbial cell factory Corynebacterium glutamicum.

Corynebacterium glutamicum is the major host for the industrial production of amino acids and has become one of the best studied model organisms in microbial biotechnology. Rational strain construction has led to an improvement of producer strains and to a variety of novel producer strains with a broad substrate and product spectrum. A key factor for the success of these approaches is detailed knowledge of transcriptional regulation in C.

Relevance of NADH Dehydrogenase and Alternative Two-Enzyme Systems for Growth of With Glucose, Lactate, and Acetate.

The oxidation of NADH with the concomitant reduction of a quinone is a crucial step in the metabolism of respiring cells. In this study, we analyzed the relevance of three different NADH oxidation systems in the actinobacterial model organism by characterizing defined mutants lacking the non-proton-pumping NADH dehydrogenase Ndh (Δ) and/or one of the alternative NADH-oxidizing enzymes, L-lactate dehydrogenase LdhA (Δ) and malate dehydrogenase Mdh (Δ). Together with the menaquinone-dependent L-lactate dehydrogenase LldD and malate:quinone oxidoreductase Mqo, the LdhA-LldD and Mdh-Mqo couples can functionally replace Ndh activity.

Molecular Basis of Growth Inhibition by Acetate of an Adenylate Cyclase-Deficient Mutant of .

In , cyclic adenosine monophosphate (cAMP) serves as an effector of the global transcriptional regulator GlxR. Synthesis of cAMP is catalyzed by the membrane-bound adenylate cyclase CyaB. In this study, we investigated the consequences of decreased intracellular cAMP levels in a Δ mutant.

Anaerobic growth of Corynebacterium glutamicum via mixed-acid fermentation.

Corynebacterium glutamicum, a model organism in microbial biotechnology, is known to metabolize glucose under oxygen-deprived conditions to l-lactate, succinate, and acetate without significant growth. This property is exploited for efficient production of lactate and succinate. Our detailed analysis revealed that marginal growth takes place under anaerobic conditions with glucose, fructose, sucrose, or ribose as a carbon and energy source but not with gluconate, pyruvate, lactate, propionate, or acetate.

Role of flavohaemoprotein Hmp and nitrate reductase NarGHJI of Corynebacterium glutamicum for coping with nitrite and nitrosative stress.

The influence of nitrate and nitrite on growth of Corynebacterium glutamicum under aerobic conditions in shake flasks was analysed. When dissolved oxygen became limiting at higher cell densities, nitrate was reduced almost stoichiometrically to nitrite by nitrate reductase (NarGHJI). The nitrite concentration also declined slowly, presumably as a result of several reactions including reduction to nitric oxide by a side-activity of nitrate reductase.

Conversion of Corynebacterium glutamicum from an aerobic respiring to an aerobic fermenting bacterium by inactivation of the respiratory chain.

In this study a comparative analysis of three Corynebacterium glutamicum ATCC 13032 respiratory chain mutants lacking either the cytochrome bd branch (ΔcydAB), or the cytochrome bc1-aa3 branch (Δqcr), or both branches was performed. The lack of cytochrome bd oxidase was inhibitory only under conditions of oxygen limitation, whereas the absence of a functional cytochrome bc1-aa3 supercomplex led to decreases in growth rate, biomass yield, respiration and proton-motive force (pmf) and a strongly increased maintenance coefficient under oxygen excess. These results show that the bc1-aa3 supercomplex is of major importance for aerobic respiration.

Physiology and global gene expression of a Corynebacterium glutamicum ΔF(1)F(O)-ATP synthase mutant devoid of oxidative phosphorylation.

A mutant of Corynebacterium glutamicum ATCC 13032 with a deletion of the atpBEFHAGDC genes encoding F(1)F(O)-ATP synthase was characterized. Whereas no growth was observed with acetate as sole carbon source, the ΔF(1)F(O) mutant reached 47% of the growth rate and 65% of the biomass of the wild type during shake-flask cultivation in glucose minimal medium. Initially, the mutant strain showed a strongly increased glucose uptake rate accompanied by a high oxygen consumption rate and pyruvate secretion into the medium.